New review maps the drivers of reproductive efficiency in sheep

Sheep reproduction research is getting a broad, practical update with a new review in Animals that pulls together global estimates of reproductive efficiency, defined as lambs weaned per 100 breeding ewes, and links that outcome to three core drivers: ewe fertility, fecundity, and lamb survival. The paper, by David O. Kleemann, Alyce M. Lowe, and Alice C. Weaver, examines how those measures vary across breed classes, countries, and regions, with the goal of clarifying where the biggest gains in flock productivity may come from. More broadly, the study lands against a backdrop of continued industry focus on sustainable intensification, with prior literature showing that reproductive efficiency in sheep is shaped not just by conception and litter size, but by whether lambs survive to weaning. (sciencedirect.com)

Why it matters: For veterinarians and sheep health advisers, the paper reinforces a familiar but important point: flock output is a systems problem, not a single-trait problem. Earlier reviews have found that reproductive traits in sheep tend to have relatively low heritability, which can limit progress from selection on any one component alone, while lamb survival remains a major constraint on overall efficiency. That makes veterinary input on pregnancy management, lambing supervision, neonatal care, nutrition, infectious disease control, and heat-stress mitigation especially relevant when producers are trying to improve the number of lambs weaned rather than simply the number conceived or born. (sciencedirect.com)

What to watch: Watch for whether the paper’s cross-breed and cross-region benchmarks start showing up in breeding, extension, and flock health programs that measure success by lambs weaned, not just pregnancy rate.